This invention relates to methods for extracting vanadium pentoxide from vanadium-containing materials. These methods are widely used in non-ferrous metallurgy, and particularly in hydrometallurgy.
A method is known in the prior art for isolating vanadium pentoxide from materials containing vanadium, in which the vanadium-containing metallurgical slags, disintegrated to a particle size of less than 0.1 mm and roasted in an oxidizing medium, are processed with a solution of sulphuric acid see for example `Chemistry of Rare and Scattered Elements`, edited by K. A. Bolshakov, Higher School Publishers, Moscow, 1969, vol. II, p. 486 ).
The known method, however, does not ensure the desired degree of vanadium extraction, especially from slags containing large amounts of calcium oxide.
Moreover, the known method makes it impossible to utilize in agriculture (as fertilizers) the solid residue containing, in addition to microelements such as vanadium, manganese and others, calcium oxide in the form of gypsum.
Furthermore, the known method limits the calcium oxide content of slags (due to difficult filtration) which makes it impossible to prepare them by a single-step process.